Without limiting the scope of the invention, its background is described in connection with sampling of blood. Particularly popular for glucose measure measurements, blood sampling devices, also known as lancing devices, are known for piercing the skin to produce blood for analysis. Typically, a drop of blood for this type of analysis is obtained by making a small incision in the skin with a quick-action fine needle, or lancet, to create a small wound that generates a small blood droplet on the surface of the skin. However, repeatability, comfort, and safety of lancing devices have been limited up to this point.
For example, early methods of lancing included piercing or slicing the skin with a needle or razor. Current methods utilize lancing devices that drive the lancet by a variety of mechanisms such as springs, pistons, and lasers. The tests are performed by a prick of a finger with a lancet to get a drop of blood. For example, the device may be held against the skin and mechanically triggered to launch the lancet as a retractable projectile. Unfortunately, the pain associated with a lancing event using known technology often discourages patients from testing and subsequent compliance. Further, in addition to vibratory stimulation of the skin as the lancet impacts the end of a launcher stop, known spring based devices can also cause recoil and multiple strikes because of the possibility of harmonically oscillating against the patient tissue.
Another barrier to patient compliance is the lack of spontaneous blood flow generated by known lancing technology. In addition to the pain as discussed above, a patient may need more than one lancing event to obtain a blood sample since spontaneous blood generation is unreliable using known lancing technology. Thus the pain is multiplied by the number of tries it takes to successfully generate spontaneous blood flow. Different skin thickness and amounts of vasoconstriction may yield different results in terms of pain perception, blood yield and success rate of obtaining blood between different users of the lancing device.
A still further barrier to improved compliance is the many steps and hassle associated with each lancing event. Many patients need to self-test for blood component levels five to six times daily. The large number of steps required in traditional methods of blood testing, ranging from lancing, to milking of blood, applying blood to the test strip, and getting the measurements from the test strip, discourages many patients from testing their blood as often as recommended. Older patients and those with deteriorating motor skills encounter difficulty loading lancets into launcher devices, transferring blood onto a test strip, or inserting thin test strips into slots on blood measurement meters. Additionally, the wound channel left on the patient by known systems may also be of a size that discourages those who are active with their hands or who are worried about healing of those wound channels.
Accordingly, what are needed are methods and apparatus to deliver improved speed, repeatability, comfort, and safety to lancing devices for blood sampling.